Please explain why my 21" Sony Trinitron video monitor (no UHF decoder) displayed Never Twice the Same Colour hue changes when using NTSC screenmodes, and correct PAL colour when using PAL screenmodes, from the composite output of my A1200.
Well, that is a very good question. Without knowing for sure the details of what signal is being outputted and what the monitor is doing with it, I couldn't really tell you. Heck, maybe even something in one of the motherboard revs or RF/Composite boxes is different between various A1200s.
This is a topic that confuses me, and honestly, I don't know the answers. My empirical data consists of one TV that can supposedly accept PAL or NTSC by changing a couple settings in a hidden unlock menu. When set to PAL, I get erratic lose color losses out of my NTSC A1200's PAL mode. It worked fine with my friend's native PAL CD32, though.
Take THAT ball of confusion for what it's worth. The PAL-N/PAL-M explanation was the only thing I've heard that made sense, but it may well be in error. I don't have the equipment or experience to really say for sure.
ETA: Actually, a lot of the color encoding hassles may be limited to the A1200 RF port only, but I'm not sure.